Giant Prolactinoma Causing Proptosis and Stroke

Abstract

Background: Although suprasellar and cavernous sinus invasion are common in giant prolactinomas, intra-orbital extension is extremely uncommon [1]. Even less reported are cases of giant prolactinomas causing cerebral ischemia or death.Clinical Case: A 51-year old woman presented to the ED with confusion, right-sided weakness and severe left eye proptosis with loss of vision. Five years prior, she underwent a partial transphenoidal resection for a macroprolactinoma due to acute vision changes with compression of the optic chiasm. Prior to surgery, prolactin level was elevated to 2,106 ng/mL (n 2.4-24.0 ng/mL). Post-operative MRI showed residual 2.7 x 3.1 x 2.6 cm mass. Thereafter she was prescribed cabergoline which she self-discontinued three years later. MRI of the brain at time of presentation demonstrated a 10.1 x 6.4 x 4.3 cm sellar/suprasellar mass extending into the left orbit causing severe proptosis and mass effect on the left frontal lobe, temporal lobe, midbrain, and basilar artery with encasement of the left cavernous internal carotid artery. A recent left striatocapsular infarct due to compression of the left middle cerebral artery was present. Prolactin level was elevated to 16,487 ng/mL. Neurosurgery was consulted and recommended medical management. Free thyroxine level was low and thyroid hormone replacement was started. Although the cosyntropin stimulation test showed an appropriate cortisol level peak of 21.5 mcg/dL, she was given stress dose glucocorticoids. Bromocriptine was initially started and titrated and later changed to cabergoline. Six weeks after discharge, she was readmitted with worsening confusion and seizure activity. On day 2 of admission, she decompensated. New hemorrhage inside the mass with increased vasogenic edema and a midline shift was discovered on a head CT. She underwent emergent craniotomy with surgical debulking of the tumor. Unfortunately, her mental status did not improve post-operatively. She was transitioned to hospice care and died 7 days after surgery. Surgical pathology showed a lactotroph adenoma with markedly elevated Ki67 proliferation index of 20-30%.Conclusion: This case demonstrates an unusually aggressive macroprolactinoma causing severe proptosis, ischemic stroke and death and adds to the very few cases previously reported [2].